1.Solder Mask Bridge: The oil between two pins of component is solder mask bridge, generally refers to intensive IC pin (check the below picture). If the distance of pin is too small, it will be recommended to cancel the solder mask bridge and take advantage of solder mask opening technology.
2.Solder Mask Openings: the place without solder mask calls solder mask opening
3.PCBWay can accept IC pad spacing down to 0.19 mm when using green, blue, red, or purple solder mask. For other solder mask colors, the minimum IC pad spacing should be 0.22 mm. When the spacing is below these values, we recommend using solder mask openings.
Solder mask clearance: the suggested soldermask clearance in GERBER is 2-4 mils.
